To find your optimal panel angle:
Use the Solar Panel Tilt Calculator to find seasonal and year-round tilt angles based on your latitude, and compare roof orientations.
Solar & Photovoltaic Planning
Calculate solar panel tilt angles, model monthly solar production using PVWatts, estimate array sizing, and plan off-grid solar battery storage with transparent formulas.
Find a latitude-based starting panel angle, then compare your roof geometry with modeled production when available.
Estimate monthly and annual solar production for your location using system size and editable PVWatts assumptions.
Estimate solar battery bank energy capacity from daily load, autonomy, SOC, efficiency and planning margin.
Estimate daily appliance energy from watts, schedules, duty-cycle assumptions and essential-load planning.
Estimate solar system size and panel count from your energy target, panel wattage and modeled solar yield.
Interactive Planning Journey
Follow our 4-step engineering sequence to plan a complete grid-tied or off-grid photovoltaic system from appliance energy demand to storage:
Tally your household appliance schedules, duty cycles, and peak running watts.
Calculate required DC nameplate capacity in kW and exact number of 400W panels.
Simulate month-by-month AC generation using NREL location irradiance data.
Size nominal kWh and Ah battery capacity for continuous multi-day cloudy autonomy.
Calculations, electrical losses, and design safety margins adhere to recognized engineering guidelines:
Standardized location-aware solar irradiance, temperature derate, and inverter AC output modeling.
Standards governing PV array circuit sizing, overcurrent protection, and rapid shutdown requirements.
Design qualification and type approval for crystalline silicon photovoltaic modules.
Use the Solar Panel Tilt Calculator to find seasonal and year-round tilt angles based on your latitude, and compare roof orientations.
Use the Solar Panel Size Calculator to determine kW capacity and panel count, then the Solar Panel Output Calculator for location-specific monthly kWh yield.
Use the Solar Load Calculator to tally daily appliance energy, then the Solar Battery Bank Size Calculator to size your backup storage.
Our solar tools pair local geometry heuristics with NREL PVWatts V8 solar irradiance data. Every technical assumption (losses, inverter efficiency, DC-to-AC ratio) is visible and user-editable.